The SAD_ScBulkUpdateMultiProxy function converts any proxy addresses on the server from one of the old site proxy addresses to one of the new site proxy addresses.
If a proxy address contains rgwszOldSiteAddress[n], that site portion of the address is converted to rgwszNewSiteAddress[n], as expected. If either rgwszOldSiteAddress[] or rgwszNewSiteAddress[] does not have cwszSiteAddress entries, SAD_ScBulkUpdateMultiProxy returns SC_BPSiteAddressMismatch.